'Stair-Step' display of trace

joe W4RYW All Messages By This Member #15056 I have a new TSA-Ultra with latest FW, All self tests & cal worked ok. Unit seems to be performing as expected. I set the freq to cover the US AM broadcast band 530-1720 Khz & got a curious stair-step trace on the lower half of the band which seems to obscure the noise floor. It is quite visible if the range is set from 800 to 1000KHz. Scans for other ranges above 1 Mhz are fine. Maybe I have something set wrong? Joe
Peter Finch All Messages By This Member #15058 Mine looks pretty much the same. Brand new tinySA Ultra.
Erik Kaashoek All Messages By This Member #15059 This is normal behavior. -- Designer of the tinySA For more info go to https://tinysa.org/wiki/
Stuart Landau All Messages By This Member #15061 It looks like the front-end attenuator is slowly autoranging. Stuart K6YAZ Los Angeles, California
Erik Kaashoek All Messages By This Member #15062 Its actually the AGC inside the power detector. Once the zero Hz peak moves outside its detection window, the gain can increase and the noise floor drops in steps/ -- Designer of the tinySA For more info go to https://tinysa.org/wiki/
joe W4RYW All Messages By This Member #15068 On Fri, Feb 16, 2024 at 05:15 AM, Erik Kaashoek wrote: Its actually the AGC inside the power detector. Once the zero Hz peak moves outside its detection window, the gain can increase and the noise floor drops in steps/ Thanks for the clarification & all your great work!

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